Senator Dianne Feinstein, who has previously run for governor, would beat Brown in the primary, according to polls conducted earlier this year, but Feinstein has expressed little interest in the job, at least publicly.

Congressperson Jane Harman, who represents Venice in Southern California, is independently wealthy and has name recognition in the more populous southland.

State Controller Steve Westly has also run in the past, but was unable to beat real estate developer Phil Angelides in the last primary, so it's unlikely he'd stand a chance against Brown.

Los Angeles Mayor Antonio Villaraigosa ended speculation about a rumored run for governor just a few months ago, which left Congressperson Loretta Sanchez on the tip of political tongues as another southland Democrat with likely appeal to latino voters.

If there's a dark horse, it's likely State Treasurer Bill Lockyer, who has millions already raised in a campaign warchest, but has said he plans to seek another term as treasurer.

Newsom's departure also raises questions about San Francisco's future. While there are rumors he might instead run for lieutenant governor, a victory would allow the Board of Supervisors to appoint his replacement -- and no Newsom supporter likes that scenario.

It will be interesting to see the moves other likely candidates make, including City Attorney Dennis Herrera, Public Defender Jeff Adachi and Supervisor Ross Mirkarimi. If they learned anything from Newsom, it may be time to start dialing for dollars early and often.

Jackson West figures a Brown nomination is inevitable unless Harman, Sanchez or certainly Feinstein make a splashy declaration.